bonedaddy41

My Feedback: (2)

Everybody "knows" that we are suppose to perform checks and maintenance on our planes and equipment on a regular basis – but sometimes we forget I was reminded of that lesson again last weekend – the hard way. Luckily, nobody was hurt and I did not lose a plane. But it is pretty scary when you think about what “could have happened”.

I decided to fly a plane that had been sitting for about a year. It flew well the last time I took it out so I didn’t have any concerns about pre-flight check other than the normal – charge/load test, ensure proper flight surface movement with no sloppiness/binding, make sure everything is tight, etc.

That last item can cover a LOT that we take for granted. I am the type of person that takes pride in the appearance of my planes and equipment. I tend to overspend to get the best money can buy. All of my gas planes run carbon fiber spinners which require the use of a thread-lock agent of some sort on the 6 screws that hold the CF spinner to its backplate. This makes the spinner something that you simply do not take off unless you absolutely have to. So I never even thought about taking that spinner off to check the prop bolts. []

Apparently, the NX 24x8 wood prop that was mounted to the front of my Evolution 58GX shrunk after getting hot and cold in my garage for a year. Obviously the prop was tight the last time I flew the plane – but when we started it to run a little gas through it before flying – it sounded like a washing machine full of marbles. I was afraid that I had some bearings get rusty after sitting – but on further investigation, I had sheared 2 prop bolts off at the hub and bent the other 4 bolts.

Luckily I was able to replace the bolts and all is well. This lesson just drives home the need to check EVERYTHING on a regular basis, even the stuff that is not easy to get to.

foodstick

At our club one of the biggest problems is keeping everyone starting planes with the motor pointing out of the pits, A prop incident is always possible in many ways.. I have seen some oddball accidents that have so far only hurt planes...not people. I am glad you had that much luck this time... I wish everyone would stay behind their motors as much as possible and keep them pointed out of the pits... bloody accidents RUIN the day !!

pe reivers

wooden props need a bolt check on a very regular basis, because the wood takes a set under load. Depending on the wood quality, that set can be up to 60% of the original thickness! Balso even has more, but that is not used for gas engine props.
The darker and denser the wood, the less the set, but still.
Plastics, the fibre reinforced once included also take a set, so the prop bolts must be checked there as well. Engine manufacturers even specify to perform this check BEFORE every flight. Indeed with blond wood props I often found the prop quite loose after a single tankful of fuel through the engine.

outssider

My Feedback: (23)

i have noticed this with new props especially. after a prop has been on for a while it doesn't need checking as often. go easy on the tighening, no need to go nuts about the amount of torque.

pe reivers

with the number of screws, it is indeed sensible to torque just lightly in order not to compress the wood beyond it's limits. Just torque very evenly.

JoeAirPort

My Feedback: (41)

This is why I have never been able to buy those CF spinners. I'm always removing my props to work on the engine or something. I just get the alum ones with lightened back plate a la True Turn.

Good heads up though. I will make sure to check my prop bolts often.

Rafael23cc

My Feedback: (6)

The giant scale guys at my field always loosen the prop bolts at the end of the day, and re-tighten them at the begining of the flying day. It seems to be a good thing to do. Lets the prop hub relax from the crushing pressure of the prop bolts.

Rafael

skyesdad

My Feedback: (1)

but now she is all better and rippin away

flatlandmike

My Feedback: (17)

Guys i found and have been using this cf spinner thats center bolt like a true turn check em out.

TBM has a similar one but this company has proved itself to me.

http://azurehobbies.com/product_info...products_id=84

bonedaddy41

My Feedback: (2)

Thanks Mike. I bookmarked that site.

That is the real beauty of RCU - we do something really stupid and tell everybody in the world about it - you can always count on Pe to have all of the technical info you need - you always have someone that hints (thru PM) at the fact that you really are stupid and they would never have anything like that happen (I am surprised I didn't get a single "f%^&ing idiot" )- most people see the post for what it is meant for - your flying buddies from your club can chip in with a calming note - and then somebody like Mike comes up with the perfect solution. I will definately try one of those spinners.

pe reivers

If I am to use wood props, there is no spinner. The spinners I have (using carbon props) all have the central bolt fastening.
I do sell very bling carbon spinners with side screws though, but these can only be used with Mejzlik props which do not seem to show any relaxing of the prop bolts.